Energy storage cell

Abstract

The present invention provides a power storage cell capable of suppressing the crushing (damage) of the uncoated portion of the electrode layer where the tabs are connected. [Solution] The energy storage cell 100 includes an electrode body 10 including a first electrode 10A, and a first tab 90A that electrically connects the first electrode 10A and a first connecting member 50A. The first electrode 10A includes a first current collector 11A and a first active material layer 12A. The first current collector 11A includes an insulating support layer 110 and a first conductive layer 111 formed on the insulating support layer 110. The first conductive layer 111 has a first uncoated portion 111b that is exposed from the first active material layer 12A. The first uncoated portion 111b includes a first connecting portion 111c to which the first tab 90A is connected. The thickness t11 of the first connecting portion 111c is greater than the thickness t12 of the first coated portion 111a.

Description

Technical Field

[0001] The present disclosure relates to a storage battery cell.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2019-96591 (Patent Document 1) discloses an electrode member including an electrode body and a conductive structure. The electrode body includes an insulating substrate and a conductive layer provided on the surface of the insulating substrate. The conductive layer has a first portion coated with an active material and a second portion to which the conductive structure is connected without coating the active material.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above Patent Document 1, as described above, the conductive structure (tab) is connected to the second portion (uncoated portion) of the conductive layer (electrode layer). Therefore, the second portion may be crushed (damaged) due to the connection with the conductive structure.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a storage battery cell capable of suppressing the crushing (damage) of the portion of the uncoated portion of the electrode layer to which the tab is connected.

Means for Solving the Problems

[0006] A power storage cell according to one aspect of the present disclosure comprises an electrode body including an electrode sheet, a current collector electrically connected to the electrode sheet, and a tab electrically connecting the electrode sheet and the current collector. The electrode sheet includes a conductive sheet and an electrode active material layer formed on the conductive sheet. The conductive sheet includes an insulating support layer and an electrode layer formed on the insulating support layer. The electrode layer has a coated portion on which the electrode active material layer is formed, and an uncoated portion exposed from the electrode active material layer. The uncoated portion includes a connecting portion to which the tab is connected. The thickness of the connecting portion of the uncoated portion is greater than the thickness of the coated portion. [Effects of the Invention]

[0007] According to this disclosure, it is possible to suppress the crushing (damage) of the portion of the uncoated electrode layer where the tabs are connected. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view showing the configuration of the energy storage device and frame members according to this embodiment. [Figure 2] This is a perspective view showing the configuration of the energy storage cell according to this embodiment. [Figure 3] This is an exploded perspective view showing the configuration of the energy storage cell according to this embodiment. [Figure 4] This is a cross-sectional view of the electrode body according to this embodiment. [Figure 5] This is a cross-sectional view showing the configuration of the first tab and the first electrode according to this embodiment. [Figure 6] This is a schematic, partially enlarged view of Figure 5. [Figure 7] This is a cross-sectional view showing the configuration of the first tab and the first electrode according to a first modified example of this embodiment. [Figure 8] This is a cross-sectional view showing the configuration of the first tab and the first electrode according to a second modification of this embodiment. [Modes for carrying out the invention]

[0009] Embodiments of this disclosure will be described with reference to the drawings. In the drawings referred to below, the same or equivalent components are given the same number.

[0010] Figure 1 is a perspective view showing the configuration of an energy storage device 1 including an energy storage cell 100 in an embodiment of the present disclosure. The energy storage device 1 is mounted, for example, on a vehicle (not shown). Examples of vehicles include hybrid electric vehicles, plug-in hybrid electric vehicles, and battery electric vehicles. The energy storage device 1 may also be installed in electrical equipment other than electric vehicles (for example, a stationary energy storage device).

[0011] In this specification, the X, Y, and Z directions are mutually orthogonal directions. For example, the X and Y directions may be the front-to-back and left-to-right directions, respectively, when the energy storage device 1 is mounted on an electric vehicle. The Z direction may also be the up-and-down direction. Specifically, the Z1 and Z2 directions may be upward and downward, respectively.

[0012] The energy storage device 1 is attached to a frame member 2 located at the bottom of the vehicle. The frame member 2 is formed in a roughly rectangular cylindrical shape that surrounds the energy storage device 1.

[0013] The energy storage device 1 comprises multiple energy storage stacks 3. Each energy storage stack 3 is formed in the shape of a rectangular parallelepiped, elongated in the Y direction. The multiple energy storage stacks 3 are arranged in a line along the X direction. Each energy storage stack 3 contains multiple energy storage cells 100 arranged in the Y direction. Note that in Figure 1, for simplification, only two energy storage stacks 3 are shown, and only three energy storage cells 100 in each energy storage stack 3 are shown.

[0014] FIG. 2 is a perspective view showing the power storage cell 100 according to the present embodiment. As shown in FIG. 2, the power storage cell 100 is a so-called rectangular battery. The power storage cell 100 is a secondary battery configured to be capable of charging and discharging. The power storage cell 100 may be a secondary battery such as a lithium-ion battery or a nickel-hydrogen battery. The power storage cell 100 can be used, for example, as a cell included in a power storage module mounted on an electric vehicle.

[0015] The power storage cell 100 includes an electrode body 10, a case 20, a first external terminal 30A, a second external terminal 30B, a first terminal support portion 40A, and a second terminal support portion 40B. In FIG. 2, the electrode body 10 is schematically shown by a dashed line.

[0016] The case 20 has conductivity. The conductive portion of the case 20 is made of a metal such as aluminum. The case 20 houses the electrode body 10. The case 20 also houses an electrolytic solution (not shown).

[0017] The case 20 includes a case body 21 and a lid 22. The case body 21 includes a bottom wall 210 and a peripheral wall 211 that stands up from the bottom wall 210.

[0018] The lid 22 includes a lid body 220 and an insulating cover 221. The lid body 220 is joined to the peripheral wall 211 by welding or the like so as to close the opening of the peripheral wall 211.

[0019] The first external terminal 30A and the second external terminal 30B are provided so as to be exposed to the outside in the power storage cell 100. In the present embodiment, the first external terminal 30A is a positive electrode terminal and the second external terminal 30B is a negative electrode terminal. The first external terminal 30A and the second external terminal 30B are arranged side by side in the X direction.

[0020] The first terminal support portion 40A is locked to the lid body 220. The first terminal support portion 40A supports the first external terminal 30A from the outer circumference side of the first external terminal 30A. The second terminal support portion 40B is locked to the lid body 220. The second terminal support portion 40B supports the second external terminal 30B from the outer circumference side of the second external terminal 30B.

[0021] Figure 3 is an exploded perspective view of the energy storage cell 100 according to this embodiment. The energy storage cell 100 further comprises a first connecting member 50A, a second connecting member 50B, a first sealing ring 60A, a second sealing ring 60B, an insulating member 70, and a fuse protection unit 80. The first connecting member 50A is an example of the "current collector" of this disclosure.

[0022] The bottom wall 210 includes a bottom body 212, an outer protective film 213, and an inner protective film 214. The peripheral wall 211 rises from the bottom body 212. A pressure relief valve SV is provided in the bottom body 212. The outer protective film 213 covers the pressure relief valve SV from the outside. The inner protective film 214 covers the pressure relief valve SV from the inside. The bottom body 212 and the pressure relief valve SV are made of a metal such as aluminum.

[0023] An opening is formed at the upper end of the peripheral wall 211. The peripheral wall 211 has a substantially rectangular outer shape when viewed from the direction of the opening. The opening and the bottom wall 210 are aligned in the Z direction. The opening is located on the Z1 side of the bottom wall 210. The Z direction may be the height direction or vertical direction of the energy storage cell 100. The peripheral wall 211 is made of a metal such as aluminum.

[0024] The lid 22 further includes a sealing plug 222 and a plug cover 223. The lid body 220 has a first connecting hole 224A, a second connecting hole 224B, and an electrolyte injection hole 225. The electrolyte injection hole 225 is a through hole for injecting electrolyte into the case body 21 during the manufacturing process of the energy storage cell 100.

[0025] The sealing plug 222 seals the injection hole 225. The plug cover 223 covers the injection hole 225 and the sealing plug 222. The insulating cover 221 covers the injection hole 225, the sealing plug 222, and the plug cover 223.

[0026] The first connecting member 50A and the second connecting member 50B are conductive. At least a portion of the first connecting member 50A and the second connecting member 50B are located inside the case 20. Each of the first connecting member 50A and the second connecting member 50B is positioned opposite the electrode body 10 in the Z direction. Each of the first connecting member 50A and the second connecting member 50B is positioned on the Z1 side of the electrode body 10.

[0027] The first external terminal 30A or the first connecting member 50A is inserted through the first connecting hole 224A. The first external terminal 30A and the first connecting member 50A are joined to each other. The first connecting member 50A is joined to the electrode body 10. As a result, the first external terminal 30A is electrically connected to the electrode body 10.

[0028] The second external terminal 30B or the second connecting member 50B is inserted through the second connecting hole 224B. The second external terminal 30B and the second connecting member 50B are joined to each other. The second connecting member 50B is joined to the electrode body 10. As a result, the second external terminal 30B is electrically connected to the electrode body 10.

[0029] The first seal ring 60A is provided along the first connecting hole 224A. The first seal ring 60A is provided in the gap between the lid body 220 and the first external terminal 30A, and seals this gap. The second seal ring 60B is provided along the second connecting hole 224B. The second seal ring 60B is provided in the gap between the lid body 220 and the second external terminal 30B, and seals this gap. The first seal ring 60A and the second seal ring 60B have electrical insulating properties.

[0030] The first terminal support portion 40A includes a first locking ring 41A and a first covering ring 42A. The first locking ring 41A extends in an annular shape to surround the first connecting hole 224A and is directly locked to the lid body 220. The first covering ring 42A covers the first locking ring 41A. The first locking ring 41A supports the first external terminal 30A via the first covering ring 42A. The first covering ring 42A is made of a resin material that is electrically insulating or has relatively weak conductivity.

[0031] The second terminal support portion 40B includes a second locking ring 41B and a second covering ring 42B. The second locking ring 41B extends in an annular shape to surround the second connecting hole 224B and is directly locked to the lid body 220. The second covering ring 42B covers the second locking ring 41B. The second locking ring 41B supports the second external terminal 30B via the second covering ring 42B. The second covering ring 42B is made of an electrically insulating resin material.

[0032] The insulating member 70 has electrical insulating properties. The insulating member 70 is placed between the electrode body 10 and the case 20. The insulating member 70 electrically insulates the electrode body 10 and the case 20 from each other. The insulating member 70 includes an insulating bracket 71, a circumferential insulating portion 72, a bottom insulating portion 73, and adhesive tape 74.

[0033] The insulating bracket 71 is positioned between the electrode body 10 and the lid body 220. The insulating bracket 71 is relatively rigid and is in contact with both the electrode body 10 and the lid body 220. As a result, the electrode body 10 is fixed to the case 20 in the Z direction.

[0034] The circumferential insulating portion 72 is positioned between the electrode body 10 and the circumferential wall 211. The electrode body 10 is made of a film-like material.

[0035] The bottom insulating portion 73 is positioned between the electrode body 10 and the bottom wall 210. The bottom insulating portion 73 is made of a film-like material. The bottom insulating portion 73 is fixed (adhered) to the case 20 (bottom wall 210) by adhesive tape 74.

[0036] The energy storage cell 100 according to this embodiment includes a plurality of electrode bodies 10. The energy storage cell 100 of this embodiment includes two electrode bodies 10. These electrode bodies 10 are arranged in the Y direction. The circumferential insulating portion 72 may integrally cover the plurality of electrode bodies 10 so that these electrode bodies 10 are fixed to each other.

[0037] Each of the multiple electrode bodies 10 is provided with at least one first tab 90A and at least one second tab 90B. In this embodiment, each of the multiple electrode bodies 10 is provided with multiple first tabs 90A and multiple second tabs 90B. Each first tab 90A electrically connects the first electrode 10A (described later) and the first connecting member 50A. Each second tab 90B electrically connects the second electrode 10B (described later) and the second connecting member 50B. Note that the first tab 90A is an example of a "tab" in this disclosure.

[0038] Multiple first tabs 90A are arranged so as to be aligned with each other in the Y direction. Multiple first tabs 90A are joined to each other, for example by ultrasonic welding. Multiple first tabs 90A are joined to the first connecting member 50A, for example by ultrasonic welding. Multiple second tabs 90B are arranged so as to be aligned with each other in the Y direction. Multiple second tabs 90B are joined to each other, for example by ultrasonic welding. Multiple second tabs 90B are joined to the second connecting member 50B, for example by ultrasonic welding.

[0039] Figure 4 is a cross-sectional view of the electrode body 10 in the XY plane. The electrode body 10 includes a first electrode 10A, a second electrode 10B, a separator 10C, and a tape member 10D. The electrode body 10 is wound such that the first electrode 10A, the second electrode 10B, and the separator 10C surround the winding axis α. Thus, in this embodiment, the electrode body 10 is a so-called wound electrode body, but it may also be a laminated electrode body in which the first electrode 10A, the second electrode 10B, and the separator 10C are stacked in one direction (for example, the Y direction). The first electrode 10A is an example of the "electrode sheet" of this disclosure.

[0040] The first electrode 10A and the second electrode 10B have a sheet-like outer shape. The electrode body 10 is composed of a group of electrode plates in which the first electrode 10A and the second electrode 10B are wound around one or more separators 10C.

[0041] In this embodiment, the first electrode 10A is the positive electrode and the second electrode 10B is the negative electrode. However, the first electrode 10A may be the negative electrode and the second electrode 10B may be the positive electrode.

[0042] The separator 10C is provided between the first electrode 10A and the second electrode 10B. The separator 10C separates the first electrode 10A and the second electrode 10B while allowing ions to move between them. The ions are, for example, lithium ions. The separator 10C has electrical insulating properties.

[0043] Of the first electrode 10A, the second electrode 10B, and the separator 10C, the separator 10C is located on the innermost side with respect to the winding axis α. Also, of the first electrode 10A, the second electrode 10B, and the separator 10C, the separator 10C is located on the outermost side with respect to the winding axis α. The outer edge of the separator 10C in the winding direction is fixed by a tape member 10D placed on the outer surface of the separator 10C.

[0044] The first electrode 10A includes a first current collector 11A and a first active material layer 12A. The second electrode 10B includes a second current collector 11B and a second active material layer 12B. The first current collector 11A and the first active material layer 12A are examples of the "conductive sheet" and "electrode active material layer" of this disclosure, respectively.

[0045] Figure 5 is a cross-sectional view of the first electrode 10A and the first tab 90A. The first current collector 11A includes an insulating support layer 110, a first conductive layer 111, and a second conductive layer 112. The first electrode 10A further includes a protective portion 13. The first conductive layer 111 is an example of the "electrode layer" and "first electrode film" of this disclosure. The second conductive layer 112 is also an example of the "electrode layer" and "second electrode film" of this disclosure.

[0046] The insulating support layer 110 has a first surface 110a and a second surface 110b. The second surface 110b is provided on the opposite side from the first surface 110a. The first conductive layer 111 is located on the first surface 110a. The second conductive layer 112 is located on the second surface 110b. The thickness t1 of the insulating support layer 110 is constant. In the following description, "thickness" refers to the thickness in the thickness direction DT, and "constant thickness" means that the thickness does not change as the position in the Z direction changes. The thickness direction DT is the direction in which the first surface 110a and the second surface 110b are arranged. That is, the thickness direction DT is an example of the "arrangement direction" in this disclosure.

[0047] The insulating support layer 110 is made of an electrically insulating resin composition. For example, the insulating support layer 110 is made of a resin composition containing a polyester resin. The polyester resin is preferably polyethylene terephthalate, for example. This makes it possible to increase the rigidity of the first current collector 11A while maintaining the electrical insulation properties of the insulating support layer 110. Consequently, the insulating support layer 110 can be made relatively thin. The orthogonal direction DO that intersects (is perpendicular to) the thickness direction DT of the insulating support layer 110 is substantially parallel to the Z direction. Note that the Z direction (orthogonal direction DO) is an example of the "intersecting direction" in this disclosure.

[0048] The first conductive layer 111 is located on the winding axis α side when viewed from the insulating support layer 110. The first conductive layer 111 may also be provided across the entire surface of the first surface 110a of the insulating support layer 110.

[0049] The second conductive layer 112 is located on the opposite side of the winding axis α when viewed from the insulating support layer 110. Furthermore, the second conductive layer 112 may be provided across the entire surface of the second surface 110b of the insulating support layer 110.

[0050] Each of the first conductive layer 111 and the second conductive layer 112 is made of a metal layer. Each of the first conductive layer 111 and the second conductive layer 112 is made of a metal containing aluminum. As a result, the first current collector 11A can be suitably used as a positive electrode current collector. The first current collector 11A may also be a negative electrode current collector, and the first conductive layer 111 and the second conductive layer 112 may be made of a metal containing copper.

[0051] Each of the multiple first tabs 90A is joined to the first conductive layer 111 and the second conductive layer 112, for example, by ultrasonic welding. Each of the multiple first tabs 90A extends from the insulating support layer 110 toward Z1.

[0052] The first conductive layer 111 includes a first coated portion 111a and a first uncoated portion 111b. The first coated portion 111a is the portion of the first conductive layer 111 on which the first active material layer 12A is formed. The first uncoated portion 111b is the portion of the first conductive layer 111 that is exposed from the first active material layer 12A. The first coated portion 111a and the first uncoated portion 111b are examples of the "coated portion" and "uncoated portion" as defined in this disclosure.

[0053] The second conductive layer 112 includes a second coated portion 112a and a second uncoated portion 112b. The second coated portion 112a is the portion of the second conductive layer 112 on which the first active material layer 12A is formed. The second uncoated portion 112b is the portion of the second conductive layer 112 that is exposed from the first active material layer 12A. The second coated portion 112a and the second uncoated portion 112b are examples of the "coated portion" and "uncoated portion" as defined in this disclosure, respectively.

[0054] Each of the multiple first tabs 90A includes a first foil portion 91 and a second foil portion 92. The first foil portion 91 is located on the opposite side of the insulating support layer 110 when viewed from the first conductive layer 111. The first foil portion 91 is bonded to the first conductive layer 111. The first foil portion 91 is bonded to the first connecting member 50A. The second foil portion 92 is located on the opposite side of the insulating support layer 110 when viewed from the second conductive layer 112. The second foil portion 92 is bonded to the second conductive layer 112. Note that the first foil portion 91 and the second foil portion 92 are examples of the "first tab piece" and "second tab piece" of this disclosure, respectively.

[0055] The first uncoated portion 111b includes a first connecting portion 111c to which the first foil portion 91 is connected. The second uncoated portion 112b includes a second connecting portion 112c to which the second foil portion 92 is connected. The first connecting portion 111c and the second connecting portion 112c are located in the same area in the Z direction. The first connecting portion 111c is an example of a "connecting portion" in this disclosure.

[0056] The first foil portion 91 includes a lower portion 91a and an upper portion 91b. The lower portion 91a is the part of the first foil portion 91 that is positioned on the first current collector 11A. The upper portion 91b is the part that protrudes from the lower portion 91a toward the Z1 side (the first connecting member 50A side).

[0057] The second foil portion 92 includes a lower portion 92a and an upper portion 92b. The lower portion 92a is the part of the second foil portion 92 that is positioned on the first current collector 11A. The upper portion 92b is the part that protrudes from the lower portion 92a toward the Z1 side (the first connecting member 50A side).

[0058] The upper portion 91b is joined to the upper portion 92b. Specifically, the upper portion 91b and the upper portion 92b are joined at the joint portion 93 on the Z1 side of the first current collector 11A, for example by ultrasonic welding.

[0059] The first foil portion 91 (upper portion 91b) extends further toward Z1 than the upper end portion 92c (Z1 side end) of the second foil portion 92 (upper portion 92b). The joint portion 93 is the portion where the upper portion 92b and the Z2 side base portion of the upper portion 91b are joined. The joint portion 93 extends toward Z1 from, for example, the upper end portion 10E of the electrode body 10. The upper end portion 10E of the electrode body 10 is the upper end portion of the separator 10C (Figure 4). The lower end portion of the joint portion 93 may be located, for example, toward Z1 or Z2 than the upper end portion 10E.

[0060] As described above, the length of the first foil portion 91 in the orthogonal direction DO (Z direction) perpendicular to the thickness direction DT is longer than the length of the second foil portion 92 in the orthogonal direction DO. However, the configuration of the first tab 90A is not limited to this. The length of the second foil portion 92 in the orthogonal direction DO may be longer than the length of the first foil portion 91 in the orthogonal direction DO. Furthermore, the second foil portion 92 may be joined to the first connecting member 50A, while the first foil portion 91 may not be joined to the first connecting member 50A.

[0061] The first active material layer 12A includes an inner active material layer 121A and an outer active material layer 122A. The inner active material layer 121A is laminated on the first conductive layer 111 (first coated portion 111a). The outer active material layer 122A is laminated on the second conductive layer 112 (second coated portion 112a).

[0062] The upper edge of the first active material layer 12A is separated from each of the multiple first tabs 90A. Specifically, the upper edge of the inner active material layer 121A is separated from each of the first foil portions 91 of the multiple first tabs 90A. The upper edge of the outer active material layer 122A is separated from each of the second foil portions 92 of the multiple first tabs 90A.

[0063] The separator 10C is laminated on the first active material layer 12A in the radial direction centered on the winding axis α (Figure 4). The separator 10C is laminated on the inner active material layer 121A in the same radial direction. The separator 10C is also laminated on the outer active material layer 122A in the same radial direction.

[0064] The protective part 13 has electrical insulating properties and is made of, for example, ceramic. The protective part 13 covers the upper part of the first active material layer 12A. The protective part 13 further covers the first current collector 11A between the first tab 90A and the first active material layer 12A.

[0065] The protective portion 13 includes an inner protective portion 131 and an outer protective portion 132. The inner protective portion 131 covers the upper part of the inner active material layer 121A. The inner protective portion 131 covers the first conductive layer 111 (first uncoated portion 111b) between the first foil portion 91 and the inner active material layer 121A. The outer protective portion 132 covers the upper part of the outer active material layer 122A. The outer protective portion 132 covers the second conductive layer 112 (second uncoated portion 112b) between the second foil portion 92 and the outer active material layer 122A.

[0066] In conventional energy storage cells, the tabs are connected to the uncoated portion of the conductive layer, which can cause the uncoated portion to be crushed (damaged).

[0067] In this embodiment, as shown in Figure 6, the thickness t11 of the first connecting portion 111c of the first uncoated portion 111b is greater than the thickness t12 of the first coated portion 111a.

[0068] Furthermore, the thickness t11 of the first connecting portion 111c is greater than the thickness t13 of the portion 111d of the first uncoated portion 111b other than the first connecting portion 111c. Portion 111d is located on the Z2 side of the first connecting portion 111c and is connected to the first connecting portion 111c. Note that its thickness t13 is equal to the thickness t12 of the first coated portion 111a.

[0069] The first foil portion 91 protrudes further towards Z2 than the Z2-side end of the first connecting portion 111c. As a result, a gap Ga1 is formed between the first foil portion 91 and portion 111d. An inner protective portion 131 is placed (filled) in the gap Ga1. The inner protective portion 131 placed in the gap Ga1 may be joined to the first foil portion 91 by ultrasonic welding or the like. Alternatively, the inner protective portion 131 may not be placed in the gap Ga1, and portion 111d and the first foil portion 91 may be joined together.

[0070] Furthermore, the thickness t21 of the second connecting portion 112c of the second uncoated portion 112b is greater than the thickness t22 of the second coated portion 112a. Note that the thickness t21 may be equal to the thickness t11 of the first connecting portion 111c. Also, the thickness t22 may be equal to the thickness t12 of the first coated portion 111a.

[0071] Furthermore, the thickness t21 of the second connecting portion 112c is greater than the thickness t23 of the portion 112d of the second uncoated portion 112b other than the second connecting portion 112c. Portion 112d is located on the Z2 side of the second connecting portion 112c and is connected to the second connecting portion 112c. Note that its thickness t23 is equal to the thickness t22 of the second coated portion 112a.

[0072] The second foil portion 92 protrudes further towards Z2 than the Z2-side end of the second connecting portion 112c. As a result, a gap Ga2 is formed between the second foil portion 92 and portion 112d. An inner protective portion 132 is placed (filled) in the gap Ga2. The inner protective portion 132 placed in the gap Ga2 may be joined to the second foil portion 92 by ultrasonic welding or the like. Alternatively, the inner protective portion 132 may not be placed in the gap Ga2, and portion 112d and the second foil portion 92 may be joined together.

[0073] The first connecting portion 111c includes a first end portion 111e and a first root portion 111f. The first end portion 111e is located on the Z1 side of the first conductive layer 111, on the Z1 side, on the 111g side. The first root portion 111f is located on the Z2 side of the first end portion 111e and is connected to the first end portion 111e. Note that the end 111g is part of the first end portion 111e.

[0074] The second connection portion 112c includes a second end portion 112e and a second root portion 112f. The second end portion 112e is located on the Z1 end 112g side of the second conductive layer 112. The second root portion 112f is located on the Z2 side of the second end portion 112e and is connected to the second end portion 112e. The second end portion 112e is located on the opposite side of the insulating support layer 110 from the first end portion 111e. The second end portion 112e is separated from the first end portion 111e. The second root portion 112f is located on the opposite side of the insulating support layer 110 from the first root portion 111f. Note that the end 112g is part of the second end portion 112e.

[0075] The first end portion 111e has a surface 111h. The first root portion 111f has a surface 111i. Each of the surfaces 111h and 111i is a surface located on the side opposite to the insulating support layer 110. Surface 111h is formed continuously with surface 111i.

[0076] The first foil portion 91 (lower portion 91a) extends along the surfaces 111i and 111h.

[0077] The second end portion 112e has a surface 112h. The second root portion 112f has a surface 112i. Each of the surfaces 112h and 112i is a surface located on the side opposite to the insulating support layer 110. Surface 112h is formed continuously with surface 112i.

[0078] The second foil portion 92 (lower portion 92a) extends along the surfaces 112i and 112h.

[0079] The distance D between the surface 111h of the first end portion 111e and the surface 112h of the second end portion 112e decreases as it approaches Z1. This allows the portion of the first foil 91 extending along surface 111h and the portion of the second foil 92 extending along surface 112h to be brought closer together as they approach Z1. As a result, the first foil 91 and the second foil 92 can be easily joined together.

[0080] Specifically, the first end portion 111e has a tapered shape in which the thickness t11 decreases as it approaches the Z1 direction. The second end portion 112e has a tapered shape in which the thickness t21 decreases as it approaches the Z1 direction. The thicknesses t11 and t21 are equal at the same position in the Z direction. At least one of the thicknesses t11 of the first end portion 111e and t21 of the second end portion 112e may be constant.

[0081] In detail, the surface 111h of the first end portion 111e is inclined to approach the second end portion 112e as it approaches Z1. The surface 112h of the second end portion 112e is inclined to approach the first end portion 111e as it approaches Z1. Therefore, the first foil portion 91 is bent at the connection between surface 111h and surface 111i. The second foil portion 92 is bent at the connection between surface 112h and surface 112i. Note that each of the surfaces 111h and 112h may be flat, or they may be curved, for example, so as to be convex toward Z1.

[0082] The thickness t11 of the first root portion 111f is constant. The thickness t11 of the first root portion 111f is equal to the maximum value of the thickness t11 of the first end portion 111e. The thickness t21 of the second root portion 112f is constant. The thickness t21 of the second root portion 112f is equal to the maximum value of the thickness t21 of the second end portion 112e.

[0083] Furthermore, the thickness t11 of the first end portion 111e is minimized at the end portion 111g. The minimum value of thickness t11 is greater than the thickness t12 of the first coated portion 111a. However, the minimum value of thickness t11 may be less than the thickness t12. Also, the maximum value of thickness t11 may be more than twice the thickness t12.

[0084] The thickness t21 of the second end portion 112e is minimized at the end portion 112g. The minimum value of thickness t21 is greater than the thickness t22 of the second coated portion 112a. However, the minimum value of thickness t21 may be less than the thickness t22. Also, the maximum value of thickness t12 may be more than twice the thickness t22.

[0085] As described above, in this embodiment, the thickness t11 of the first connecting portion 111c is greater than the thickness t12 of the first coated portion 111a. This makes it possible to make the mechanical strength of the first connecting portion 111c higher than that of the first coated portion 111a. As a result, it is possible to suppress the crushing (damage) of the first connecting portion 111c.

[0086] Furthermore, the thickness t21 of the second connecting portion 112c is greater than the thickness t22 of the second coated portion 112a. This makes it possible to make the mechanical strength of the second connecting portion 112c higher than that of the second coated portion 112a. As a result, it is possible to suppress the crushing (breakage) of the second connecting portion 112c.

[0087] <First variation> Figure 7 shows a first modified example of the above embodiment. The same reference numerals are used for components that are the same as in the above embodiment.

[0088] The first electrode 300A includes a first current collector 311A. The first current collector 311A ​​has an insulating support layer 310, a first conductive layer 311, and a second conductive layer 312. The first electrode 300A and the first current collector 311A ​​are examples of the "electrode sheet" and "conductive sheet" of this disclosure, respectively. The first conductive layer 311 is an example of the "first electrode film" and "electrode layer" of this disclosure. The second conductive layer 312 is an example of the "second electrode film" and "electrode layer" of this disclosure.

[0089] The first conductive layer 311 includes a first coated portion 111a and a first uncoated portion 311b. The first uncoated portion 311b includes a first connecting portion 311c and a portion 111d. The first connecting portion 311c includes a first end portion 311e and a first root portion 111f. The first end portion 311e is located on the Z1 side of the first conductive layer 311, on the end 311g side. The end 311g is part of the first end portion 311e. The first uncoated portion 311b and the first connecting portion 311c are examples of the "uncoated portion" and "connecting portion" as defined in this disclosure, respectively.

[0090] The second conductive layer 312 includes a second coated portion 112a and a second uncoated portion 312b. The second uncoated portion 312b includes a second connecting portion 312c and a portion 112d. The second connecting portion 312c includes a second end portion 312e and a second root portion 112f. The second end portion 312e is located on the Z1 side of the second conductive layer 312, specifically on the Z1 side end 312g. The end portion 312g is a part of the second end portion 312e. The second uncoated portion 312b is an example of the "uncoated portion" in this disclosure.

[0091] The insulating support layer 310 includes an end portion 310a and a root portion 310b. The end portion 310a is located on the Z1 side of the insulating support layer 310, on the 310c side. The root portion 310b is located on the Z2 side of the end portion 310a and is connected to the end portion 310a. Note that the 310c is part of the end portion 310a. Furthermore, the end portion 310a is an example of the "third end portion" of this disclosure.

[0092] The end portion 310a has a thickness t31. The root portion 310b has a thickness t32. The thickness t32 is constant.

[0093] The thickness t31 of the end portion 310a decreases as it approaches Z1. That is, the end portion 310a has a shape that tapers towards Z1. This makes it easy to bring the surface 311h of the first end portion 311e and the surface 312h of the second end portion 312e closer together as they approach Z1. The maximum value of the thickness t31 is equal to the thickness t32 of the root portion 310b.

[0094] Specifically, the end portion 310a has a surface 310d and a surface 310e. Surface 310d is in contact with the first end portion 311e. Surface 310e is in contact with the second end portion 312e. Surface 310d is inclined so that it approaches surface 310e as it moves toward Z1. Surface 310e is inclined so that it approaches surface 310d as it moves toward Z1.

[0095] The thickness t33 of the first connecting portion 311c is constant. That is, the thickness t33 of the first end portion 311e is constant. The thickness t34 of the second connecting portion 312c is constant. That is, the thickness t34 of the second end portion 312e is constant. As a result, the first end portion 311e and the second end portion 312e can be easily formed by vapor deposition or the like. Note that at least one of the thickness t33 of the first end portion 311e and the thickness t34 of the second end portion 312e may decrease as it approaches the Z1 side.

[0096] Specifically, the surface 311h of the first end portion 311e extends parallel to the surface 310d of the end portion 310a of the insulating support layer 310. The surface 312h of the second end portion 312e extends parallel to the surface 310e of the end portion 310a of the insulating support layer 310.

[0097] The other components are the same as those in the above embodiment, so we will not repeat them.

[0098] <Second variation> Figure 8 shows a second modified example of the above embodiment. The same reference numerals are used for components that are the same as in the above embodiment.

[0099] The first electrode 400A includes a first current collector 411A. The first current collector 411A has an insulating support layer 410, a first conductive layer 411, and a second conductive layer 412. The first electrode 400A and the first current collector 411A are examples of the "electrode sheet" and "conductive sheet" of this disclosure, respectively. The first conductive layer 411 is an example of the "first electrode film" and "electrode layer" of this disclosure. The second conductive layer 412 is an example of the "second electrode film" and "electrode layer" of this disclosure.

[0100] The first conductive layer 411 includes a first coated portion 111a and a first uncoated portion 411b. The first uncoated portion 411b includes a first connecting portion 411c and a portion 111d. The first connecting portion 411c is located on the Z1 side end 411g of the first conductive layer 411 with respect to portion 111d. The end 411g is part of the first connecting portion 411c. The first uncoated portion 411b and the first connecting portion 411c are examples of the "uncoated portion" and "connecting portion" as defined in this disclosure.

[0101] The second conductive layer 412 includes a second coated portion 112a and a second uncoated portion 412b. The second uncoated portion 412b includes a second connecting portion 412c and a portion 112d. The second connecting portion 412c is located on the Z1 side end 412g of the second conductive layer 412 with respect to portion 112d. The end 412g is part of the second connecting portion 412c. The second uncoated portion 412b is an example of the "uncoated portion" in this disclosure.

[0102] The insulating support layer 410 includes an end portion 410a and a root portion 410b. The end portion 410a is located on the Z1 side end 410c of the insulating support layer 410 relative to the root portion 410b. The root portion 410b is located on the Z2 side of the end portion 410a and is connected to the end portion 410a. Note that the end 410c is part of the end portion 410a.

[0103] The first connecting portion 411c, the second connecting portion 412c, and the end portion 410a are located within the same range in the Z direction. The portion 111d, the portion 112d, and the root portion 410b are located within the same range in the Z direction.

[0104] The end portion 410a and the root portion 410b have thicknesses t41 and t42, respectively. Each of the thicknesses t41 and t42 is constant. Thickness t42 is greater than thickness t41.

[0105] The first connecting portion 411c and the second connecting portion 412c have thicknesses t43 and t44, respectively. Each of the thicknesses t43 and t44 is constant. Thickness t43 is greater than the thickness t12 of the first coated portion 111a. Thickness t44 is greater than the thickness t22 of the second coated portion 112a. Note that thickness t43 is equal to thickness t44.

[0106] The thickness of the first current collector 411A is constant. That is, the sum of thicknesses t41, t43, and t44 (t41+t43+t44) is equal to the sum of thicknesses t42, t12, and t22 (t42+t12+t22).

[0107] The other components are the same as those in the above embodiment, so we will not repeat them.

[0108] In the above embodiment, an example was shown in which the thickness t11 (t21) of the first connection portion 111c (second connection portion 112c) of the first electrode 10A is greater than the thickness t12 (t22) of the first coated portion 111a (second coated portion 112a), but the disclosure is not limited to this. The above thickness relationship in the first electrode 10A may also be applied to the second electrode 10B.

[0109] Furthermore, either the first connecting portion 111c or the second connecting portion 112c may have a thickness greater than the coated portion.

[0110] In the above embodiment, an example was shown in which each of the first end portion 111e and the second end portion 112e has a tapered shape, but the disclosure is not limited thereto. Only one of the first end portion 111e and the second end portion 112e may have a tapered shape.

[0111] In the above embodiment, an example was shown in which the first end portion 111e includes the end portion 111g of the first conductive layer 111, but the disclosure is not limited thereto. The first end portion 111e may only be provided up to the root side (Z2 side) of the end portion 111g of the first conductive layer 111. The second end portion 112e may be configured similarly.

[0112] The above embodiments and modifications show examples in which the first end portion and the second end portion are separated, but the disclosure is not limited thereto. A connecting portion may be provided to connect the first end portion and the second end portion. The connecting portion may extend along the end of the insulating support layer so as to wrap around the outside (Z1 side) of the end of the insulating support layer. In this case, the second foil portion 92 may not be provided. Furthermore, the connecting portion may be formed by immersing the end in a plating solution.

[0113] The configurations of each of the above embodiments and each of the modified examples may be combined with each other.

[0114] It should be noted that the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of this disclosure is defined by the claims rather than the description of the embodiments above, and includes all modifications within the meaning and scope equivalent to the claims. [Explanation of symbols]

[0115] 10 Electrode body, 10A, 300A, 400A First electrode (electrode sheet), 11A, 311A, 411A First current collector (conductive sheet), 12A First active material layer (electrode active material layer), 50A First connecting member (current collector), 90A First tab (tab), 91 First foil part (first tab piece), 92 Second foil part (second tab piece), 100 Energy storage cell, 110, 310, 410 Insulating support layer, 110a First surface, 110b Second surface, 111, 311, 411 First conductive layer (electrode layer) (first electrode film), 111a First coated part (coated part), 111b, 311b, 411b First uncoated part (uncoated part), 111c, 311c, 411c First connection portion (connection part), 111e, 311e First end side portion, 111g, 311g End, 111h, 311h Surface, 112, 312, 412 Second conductive layer (electrode layer) (second electrode film), 112a Second coated portion (coated part), 112b, 312b, 412b Second uncoated portion (uncoated part), 112e, 312e Second end side portion, 112h, 312h Surface, 310a End side portion (third end side portion), 310c End, D Distance, t11, t33, t43 Thickness (thickness of first connection portion) (thickness of connection part), t12 Thickness (thickness of first coated portion) (thickness of coated part), t21, t34, t44 Thickness (thickness of the second connection part) (thickness of the connection part), t22 Thickness (thickness of the second coated part) (thickness of the coated part), t31 Thickness (thickness of the third end part).

Claims

1. An electrode body including an electrode sheet, A current collector electrically connected to the electrode sheet, The electrode sheet and the current collector are electrically connected by tabs, The electrode sheet is A conductive sheet and The conductive sheet comprises an electrode active material layer formed on the conductive sheet, The aforementioned conductive sheet is Insulating support layer, The insulating support layer includes an electrode layer formed on the insulating support layer, The electrode layer includes, The coated portion on which the electrode active material layer is formed, An uncoated portion exposed from the electrode active material layer is formed, The uncoated portion includes the connecting portion to which the tab is attached. A storage cell in which the thickness of the connection portion of the uncoated portion is greater than the thickness of the coated portion.

2. The aforementioned insulating support layer is The first surface and, It has a second surface opposite to the first surface, The electrode layer is A first electrode film disposed on the first surface, The second electrode film is disposed on the second surface, The aforementioned tab is The first tab piece and, The first tab piece and the second tab piece connected to each of the current collectors, The first electrode film is The first coated portion on which the electrode active material layer is formed, This includes a first uncoated portion exposed from the electrode active material layer, The first uncoated portion includes the first connecting portion to which the first tab piece is attached. The second electrode film is The second coated portion on which the electrode active material layer is formed, This includes a second uncoated portion exposed from the electrode active material layer, The second uncoated portion includes the second connecting portion to which the second tab piece is attached. The thickness of the first connecting portion is greater than the thickness of the first coated portion. The energy storage cell according to claim 1, wherein the thickness of the second connection portion is greater than the thickness of the second coated portion.

3. If the direction in which the first surface and the second surface are aligned is defined as the alignment direction, and the direction intersecting the alignment direction is defined as the intersection direction, The first connecting portion includes the first end portion of the first electrode film that is located on one end side in the crossing direction, The second connecting portion includes a second end portion that is positioned on the opposite side from the first end portion with respect to the insulating support layer, The energy storage cell according to claim 2, wherein the distance between the surface of the first end portion and the surface of the second end portion decreases as you move toward one of the intersecting directions.

4. The energy storage cell according to claim 3, wherein the third end portion of the insulating support layer, which is located on one end side in the intersecting direction, has a thickness that decreases as it approaches the one end in the intersecting direction.

5. The energy storage cell according to claim 4, wherein the thickness of each of the first and second connection portions is constant.

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